US Patent 7633051 Spectral photoelectric measurement transformer

A spectral photoelectric measurement transformer comprises an array (10) of photoelectric transformer elements and dielectric interference bandpass filters (22a, 22b) disposed on a common filter support (21) connected upstream of them for sensitizing the transformer elements to different wavelength ranges of the measurement light. The bandpass filters are divided into a number of filter groups, each of which contains the same different bandpass filters within the filter group. An optical deflector element (30) spectrally shifts the effective bandpass curves of the bandpass filters of all the filter groups except one so that the effective bandpass curves of all the bandpass filters have different spectral positions. As a result, a multiplication of the filter channels effectively made available can be achieved using only a few different bandpass filters. Due to the small number of different bandpass filters, the measurement transformer is inexpensive to manufacture.